Method for fluent mass surface texturing a turbine vane

ABSTRACT

An apparatus and method for providing vanes with a surface texture of less than 10×10 -6  inches rms. The method employs a fluent mass having a particulate size less than 1.5 inches and abrasive materials in a centrifugal barrel to achieve a surface texture between 11-27×10 -6  inches rms. A refinement cut employs a finer abrasive and a cycle time of less than 30 minutes to provide a burnished surface texture of between 5-8×10 -6  inches rms. A final coloring cycle, employing only a coloring compound, is employed to provide a highly reflective surface texture between approximately 4-7×10 -6  inches rms.

FIELD OF THE INVENTION

This invention relates to fluent mass surface texturing, and moreparticularly to a method for employing a fluent mass to produce asurface texture of 4-7 microinches rms on a vane.

BACKGROUND OF THE INVENTION

The increased complexity and precision requirements of mechanicalproducts has enhanced the need for accurately producing and controllingthe surface texture of the manufactured parts. Variations in the surfacetexture can influence a variety of performance characteristics of thepart. The surface texture can affect the ability of the part to resistwear and fatigue; to assist or destroy effective lubrication; toincrease or decrease friction and/or abrasion with cooperating parts;and to resist corrosion. As these characteristics may become criticalunder certain operation conditions, the surface texture can dictate theperformance and integrity of the component.

Distinct surface textures may be achieved through a variety of processesincluding tumbling, vibrating, honing, lapping, polishing, turning,milling and grinding. Metal objects such as stainless steel and aluminumhave been tumbled or vibrated to remove burrs, clean, burnish and colorthe workpiece.

To accomplish these results through the tumbling or vibrating process,the prior art has manipulated the tumbling or vibrating material, thespeed and the duration of the working period. Typically, parts having arelatively small size in relation to the barrel are processed loosewithin the tumbling or vibratory material. However, in the tumblingprocess, workpieces having a relatively large size in relation to thecentrifugal barrel are usually fixed within the barrel so that theworkpiece is not damaged by contact with the barrel or other workpiecesduring the tumbling process. In addition, the prior art tumbling andvibratory processes have included both dry and wet processes, typicallyemploying rotational speeds from 12-25 rpm for the tumbling process orhigh frequency oscillations in the vibrating process. The operatingtime, while governed by the amount of tumbling or vibrating actiondesired, ranges from 1-8 hours.

The application of surface texturing techniques is especially criticalin the surfaces of vanes, such as those used in turbines, jet engines orturbomachinery. The vanes in these applications are employed atextremely high rotational speeds which produce substantial internalstresses and forces within the vane. Under these operating conditions, adefect in the surface texture may propagate to produce a fracture whichmay result in a failure of the vane. The failure of a vane duringoperating conditions results in an uncontrolled high velocity mass. Suchan uncontrolled mass can inflict substantial damage to the surroundingstructure and components, thereby rendering the entire unit inoperative,or severely damaged. Also, the surface texture may obscure or hidesurface defects, thereby preventing detection of a flawed component. Theuse of flawed components substantially increases the risk of productfracture.

In addition, these vanes operate in high temperature environments whichalso induces stress on the vane. The operating temperature of the vanemay be increased by the friction of the vane with the surrounding fluid,thereby further stressing the vane.

Although the general tumbling and vibrating processes are available, thevanes employed in jet aircraft engines are surface textured according tospecifications set forth by the vane or engine manufacturer. Themanufacturers require the finishing and refurbishment of blades incompliance with industry standard specifications. These specificationstypically require that after the vane is milled, the surface is sandedwith a belt sander. The edge radii are then hand blended to achieve anaerodynamic curvature. The vanes are shot peened and processed in avibratory bowl for a period which may exceed 4 hours. In addition, anabrasive sand blasting prior to the vibratory bowl is also required bysome manufacturers.

The processing of the vanes, as required by manufacturer'sspecifications, introduces a substantial risk to the integrity of thevanes. Specifically, the shot peening and vibratory bowl process tendsto deform the surface in such a manner so as to hide surface cracks ordefects. As these defects may later propagate into failures, the shotpeening prevents an adequate quality control of the processed vanes. Inaddition, the vibratory bowl process typically induces damage to theleading or trailing edge of the vane in approximately 10-20% of theworkpieces. If the damage to the vane is minimal, the vane is repairedby hand; however, if the damage is above a certain threshold, the entirevane must be discarded.

Further, as the vibratory bowl process typically lasts for 4 hours, theadditional handling and processing necessary to satisfy thespecifications is a time consuming and labor intensive process. Inaddition, the large amount of manual labor introduces a high percentageof inconsistent results. Further, the surface texture achieved by thespecifications produces an undesirable resistance to a passing air flow,thereby increasing fuel consumption and operating temperature of theengine.

Therefore, a need exists for a non-degrading method and apparatus forsurface texturing a vane. Further, a need exists for producing a surfacetexture which does not hide or conceal surface defects. The need alsoexists for a method which produces uniform and reproducible resultswithout requiring substantial human intervention. The need exists for anapparatus and method for providing a vane with a surface texture whichminimizes the resistance to fluid flow relative to the surface, therebyreducing operating temperatures and increasing efficiency of the vane.Finally, a need exists for a surface texturing process which does notrequire substantial processing times and materials.

SUMMARY OF THE INVENTION

A method and apparatus for producing a predetermined surface texture ona finished or unfinished vane is disclosed. The disclosed method employsa fluent mass media in a centrifugal barrel to produce the desiredsurface texture on the vanes.

The apparatus includes the centrifugal barrel which is preferablyrotated about a plurality of axes; a rack for securing a plurality ofvanes within the barrel; the fluent mass; a lubricating fluid; anabrasive material and a coloring compound.

The apparatus and method are preferably employed in three steps withrespect to an unfinished belt sanded, or milled, vane. A rough cut, arefinement cut and color cycle are employed to transform a belt sandedor milled vane into a vane having a finished surface texture of lessthan 10×10⁻⁶ inches rms. Alternatively, if the vane is only to berefinished or the existing surface texture is from approximately11-27×10⁻⁶ inches rms, the refinement cut and color cycle are employedto produce a surface texture of less than 10×10⁻⁶ inches rms.

In the disclosed process, the vanes are preferably secured in the rackand disposed within the barrel. The fluent mass, lubricating fluid,abrasive material and coloring compound are then introduced into thebarrel. Preferably, the abrasive material adheres to the surface offluent mass so as to substantially coat the mass. The barrel is closedand rotated about the axes so that the fluent mass impinges the vanes.As the fluent mass impinges the vanes, the abrasive material is disposedbetween the fluent mass and the surface of the vane, thereby removingmaterial from the surface of the vane in proportion to the energyimparted to the particulates of the fluent mass.

The abrasive material may be selected so as to provide sufficientabrasive action so as to remove material from the surface of the vane.Subsequently, the abrasive material is omitted, and the fluent mass isimpinged with just the coloring compound which nominally abrades thevane so as to provide the desired surface texture of less than 10×10⁻⁶inches rms.

The surface texture achieved by the disclosed process is determined by anumber of factors, including the rotation rate of the centrifugalbarrel; the coarseness of the abrasive material; the coloring compound,the amount of lubricating fluid; the amount, size and density of thefluent mass; the fixturing of the vanes; the direction of the mass flowrelative to the vanes; and the duration of the process.

Preferably, the factors are combined in the rough cut process to producea vane having a surface texture of approximately 11-27×10⁻⁶ inches rms,in a cycle time between 10 to 50 minutes. The duration of the rough cutprocess is a function of the surface texture of the vane prior to therough cut. Typical vane tolerances may be satisfied through the roughcut process if the surface texture is approximately 125×10⁻⁶ inches rmsprior to initiation of the rough cut. However, the rough cut may be usedto reduce a surface texture from approximately 400×10⁻⁶ inches rms to11-27×10⁻⁶ inches rms.

Preferably, the refinement process abrades and burnishes the workpieceto provide a work hardened surface texture of approximately 5-8×10⁻⁶inches rms. If the rough cut is employed to provide a pre-refinement cutsurface texture of 11-27×10⁻⁶ inches rms, the refinement cut reduces thesurface texture to approximately 5-8×10⁻⁶ inches rms in approximately 10minutes. The color cycle employs a coloring compound rather than anabrasive material to clean the surface so as to produce a highlyreflective finish, thereby making surface defects readily visible. Theuse of the coloring cycle after the refinement cut produces the 4-7×10⁻⁶inches rms surface texture is approximately 5 minutes.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a jet engine vane.

FIG. 2 is an elevational side view of a jet engine vane.

FIG. 3 is a top view of a jet engine vane showing the orientation of theblade relative to the root.

FIG. 4 is an exploded perspective view of a centrifugal barrel.

FIG. 5 is a perspective view of a centrifugal barrel in a turret.

FIGS. 6 and 7 are exploded perspective views of a rack retaining aplurality of vanes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The disclosed method and apparatus provide a surface texture ofapproximately 4-7×10⁻⁶ inches rms to a vane 10 shown in FIG. 1. Asdescribed herein, the vane 10 may include those used in a propeller,impeller, turbine, compressor, jet engine or any other turbo machinery.

Referring to FIG. 1-3, the vane 10 includes a blade 16 having a flat orcurved surface that is rotated about an axis by a fluid flow, or thatrotates to cause a fluid to flow, or that redirects a flow of fluid.Preferably, the vane 10 also includes a root 18 integrally affixed tothe blade 16. The root 18 is configured so as to engage a flange (notshown) attached to the axis about which the vane 10 is to rotate,thereby providing for retention of the vane 10 as it rotates about theaxis.

The disclosed method includes three steps which are selectively employedto provide the desired surface texture of less than 10×10⁻⁶ inches rms.The three steps include a rough cut, a refinement cut and a color cycle.Generally, the rough cut is employed on an unfinished vane 10 which hasbeen milled or coarse sanded to the general configuration of the vane.Preferably, the rough cut is used to remove the coarse sand markings soas to provide a surface texture for approximately 11-27×10⁻⁶ inches rms(110-270 millionths of an inch). However, if final manufacturingtolerances permit, it is possible to remove mill marks having a surfacetexture in the order of 400×10⁻⁶ inches rms in the rough cut. Theremaining two processes, the refinement cut and the color cycle, areused on previously finished blades, finished by either the rough cut oran alternative method, to provide a finished surface texture ofapproximately 4-7×10⁻⁶ inches rms. Preferably, the refinement cut isemployed on components having a surface texture of approximately11-27×10⁻⁶ inches rms. In addition, the refinement cut burnishes thework by imparting compressive stresses on the surface, thereby workhardening the vane 10.

The final cycle, the color cycle, is used to provide a highly reflectivesurface texture. The surface texture created by the color cycle has areduced resistance to fluid flow. In addition, the surface textureproduced by the color cycle provides for the detection of surfacedefects or flaws. Preferably, the color cycle is employed on vaneshaving a surface texture from 5-8×10⁻⁶ inches rms to produce a surfacetexture approximately 4-7×10⁻⁶ inches rms.

The apparatus for producing the surface texture includes a centrifugalbarrel 20, a fluent mass 30, a rack 40, an abrasive material 60, acoloring compound 70, and a lubricating fluid 80.

CENTRIFUGAL BARREL

The centrifugal barrel 20 houses the rack 40, the fluent mass 40, thevanes 10, the lubricating fluid, and abrasive 60 and the coloringcompound 70. Referring to FIG. 5, the barrel includes a lid 22 and bolts24. The lid 22 includes apertures 23 sized to receive the bolts 24 sothat nuts may be threaded onto the bolts 24 so as to secure and seal thelid 22 to the barrel. As shown in FIG. 5, the centrifugal barrel 20 isretained within a turret 22, which rotates about a first axis. As theturret 22 rotates about the first axis A, the barrel 20 rotates in theopposite direction within a second axis B within the orbit of the turret22. Preferably, the turret 22 includes a plurality of barrels 20 so thatmultiple batches of vanes 10 may be concurrently processed. Thecentrifugal barrel 20 may be Control Velocity Model® 1200, 1600 or 2000,as manufactured by Richwood Industries, Inc. of Garden Grove, Calif.Preferably, the opposing rotation rate of the barrel 20 about the secondaxis B is substantially equal to the rotation rate of the turret 22about the first axis A as driven by the motor of FIG. 5. Therefore, thefluent mass 30 may be moved within the barrel 20 in a substantiallypredictable path. Although the disclosed method is described in terms ofa straight rotation centrifugal barrel 20, a figure-eight barrel mayalso be employed.

Preferably, the rotational speed of the turret 22 may be varied over aspectrum of rotational velocities. It is preferable that the rotationrate of the turret 22 may be varied from 70-350 revolutions per minute.

Preferably, the turret 22 rotates at approximately 100 to 250 rpms. Theupper limit of the rotational velocity of the turret is dictated byimparting too much energy to the fluent mass 30 so that upon impingementwith the vane 10, the surface of the vane 10 is damaged. Alternatively,a rotational speed which is too low imparts insufficient energy to thefluent mass 30 so insufficient material is removed from the surface andthe desired surface texture is not obtained.

FLUENT MASS

The fluent mass 30 is employed within the barrel 20 so as to provide animpinging force upon the vanes 10 during rotation of the barrel. Theparameters which define the preferred fluent mass 30 are determined bythe process to be performed.

A. ROUGH CUT

In the rough cut process, the fluent mass 30 is chosen so that uponaddition of the abrasive material, sufficient removal of material isremoved from the surface of the vane 10 so as to remove milled or coarsesanding marks. Preferably, the rough cut produces a surface texture ofapproximately 11-27×10⁻⁶ inches on the vane 20. In the rough cutprocess, the individual particulates 32 of the fluent mass 30 may rangefrom 0.0625 inches to 1.25 inches. Although the fluent mass 30 for therough cut may be a randomly configured scientered ceramic, optimally,the range of particulate size for the rough cut process is from 4 meshto 5/8" by 1/4" pyramidal. The ceramic fluent mass 30 may comprise analuminum oxide and iron silicate compound. The preferred fluent mass 30is Richwood Media No. 62, 63 or 64.

In terms of the functional parameters which define the size of thefluent mass 30 for the rough cut process, if the fluent massparticulates 32 are too large, too much energy is imparted to the fluentmass 30 so that the vane 10 is damaged when the fluent mass impinges thesurface. In addition, if the size of the particulate 32 is too large,the surface texture of the vane 10 is above the desired level, in thatthe distance between areas of impingement of the fluent mass 30 and thevane 10 prevents the abrasive material 60 from removing a substantiallyuniform amount of material from the vane 10. Alternatively, if theparticulates 32 are too small, insufficient energy is imparted to thefluent mass 30. When the particulates are too small and thereby toolight, the inability to impart sufficient energy to the fluent massprevents the fluent mass 30 from causing the abrasive material 60 to actupon the surface, thereby rendering the process ineffective.

The density of the fluent mass 30 for the rough cut process may rangefrom 10 to 300 lbs./cubic ft., wherein the optimal range is from 85 to150 lbs./cubic ft., and the preferred density of the fluent mass for therough cut process is approximately 95 lbs./cubic ft.

B. REFINEMENT CUT

For the refinement cut, the size of the particulates 32 of the fluentmass 30 may range from 2 to 20 mesh, having an optimal range of 4 to 16mesh, and the preferred range is from 4 to 12 mesh. Preferably, theparticulates 32 are a random shaped scientered ceramic such as RichwoodMedia No. 8XM. The density of the fluent mass may vary from 10 to 300lbs./cubic ft., with a preferred range from approximately 140 to 150lbs./cubic ft. Preferably, the particulates 32 are such that sufficientenergy is imparted so as to provide enough energy to the abrasivematerial 60 so as to remove material from the surface of the vane 10. Inaddition, the refinement cut fluent mass 30 should have a sufficientmass so that, as the abrasive material 60 is pulverized, the vane isburnished.

C. COLOR CYCLE

For the color cycle, the range in size of the particulates 32 may befrom 2 to 36 mesh, wherein the preferred size is 8 mesh. Theparticulates 32 are also a scientered ceramic such as Richwood Media No.8XM. The density of the fluent mass 30 for the color cycle may rangefrom 10 to 300 lbs./cubic ft., with a preferable density ofapproximately 140 to 150 lbs./cubic ft.

For each of the rough cut, refinement cut and color cycle, the fluentmass 30 may occupy from 30% to 90% of the barrel volume, wherein theoptimal range is from 50% to 75% of the barrel volume. Preferably,approximately 65% of the barrel volume is occupied by the fluent mass.The relative volume of the fluent mass 30 is determined by thefunctional parameters, that if too little fluent mass is employed, theindividual particulates of the fluent mass are imparted with too muchenergy so that as they impinge the vane, the surface is damaged.Alternatively, if too much fluent mass 30 is employed within the barrel,an insufficient energy is imparted to the particulates 32 so that theabrasive material 60 does not remove material from the surface of thevane 10 and desired surface texture is not achieved.

RACK

As shown in FIG. 6, the rack 40 allows for the fixturing of a pluralityof vanes 10 relative to the barrel 22 and relative to the other vanes10. The fixturing of the vanes 10 allows for the volume of fluentmass-to-vane ratio to be lowered, thereby permitting a larger number ofvanes 10 to be processed in a given volume of fluent mass 30.

The rack 40 may secure the vanes 10 so that the root 18 is substantiallyprotected. That is, upon movement of the fluent mass 30 relative to therack 40, the root 18 of the vanes 10 is not exposed to the fluent mass10. Alternatively, if it is necessary, or allowable, to provide aspecific surface texture to the root 18, the rack 40 may engage the root18 so that a substantial portion of the root is exposed. The exactconfiguration of the rack 40 as it engages the roots 18 is determined bythe necessity of protecting or exposing the root.

Preferably, as shown in FIGS. 6 and 7, the rack 40 includes a pair ofparallel struts 42 which are separated by a plurality of supports 44having apertures 45 in opposing ends. The struts 42 include spacedapertures 46, 47, sized to receive a pin 48, 49, respectively. Inaddition, the rack 40 may include legs 52 having apertures 57. To securea vane 10 relative to the rack 40, the root 18 is disposed betweenadjacent supports 44. The supports 44 are secured by passing pin 48through aperture 46 into aperture 45. As shown in FIG. 6, a plurality ofvanes may be secured between adjacent supports 44 so that the vanes willnot contact each other.

The rack 40 may be attached to a lid 22 of the barrel 20 so as to securethe vanes 10 relative to the barrel 20. Alternatively, the legs 52 maybe secured to the struts 42 by passing pin 49 through aperture 47 intoaperture 57. The legged rack may then be disposed or wedged between thelid and the bottom of the barrel so as to prevent motion of the rack 40relative to the barrel 20.

ABRASIVES

During the rough cut and refinement cut steps, the abrasive material 60is employed with the fluent mass 30 so as to remove material from thesurface of the vane 10. Preferably, the abrasive material 60 comprises afine powder which substantially adheres to the surface of theparticulates 32 so that as the fluent mass 30 impinges the vane 10, theabrasive 60 is disposed between the surface of the vane and the fluentmass. The abrasive material 60 used in the rough and refinement cuts mayrange from 24 grit to 1600 grit, depending upon the surface textureprior to initiation of the disclosed method.

In terms of functional parameters, if the abrasive 60 is too coarse, toomuch material is removed from the surface of the vane 10 as the fluentmass 30 impinges the vane 10, thereby preventing the surface texturefrom achieving the desired smoothness. Alternatively, if the abrasivematerial 60 is too fine, insufficient material is removed from thesurface during impingement of the fluent mass 30 and the vane 10 so thatthe process is inefficient. In addition, the amount of abrasive material60 employed during the rough and refinement cuts affects the amount ofmaterial removed from the surface of the vane. For a given abrasive 60,the more abrasive that is employed during a cut, the more aggressive theabrasion of the vane 10.

Preferably, an abrasive of between 24-500 grit is employed in the roughcut. The abrasive material 60 for the rough cut may comprise aluminumoxide, silicon carbide, garnet, silica sand, boron carbide or fusedaluminum oxide, with quantities of phosphate, borax, surfactants,inhibitors and non-ionic detergents so as to have a specific gravity ofapproximately 1.4 and a solubility in water of approximately 8%. Apreferred abrasive material 60 for the rough cut is Richwood CompoundNo. 40 by Richwood Industries, Inc. of Garden Grove, Calif.

Preferably, the abrasive material 60 for the refinement cut includes anabrasive such as aluminum oxide, silicon carbide, garnet, silica sand,boron carbide, brown or white fused aluminum oxide having a grit from150 to 1600, and soaps and detergents so as to form a powder which issubstantially insoluble in water. The abrasive material 60 employed inthe refinement cut provides two functions. Early in the refinement cut,the integrity of the abrasive material 60 is substantially constant sothat material is removed from the surface of the vane 10. However,during the later portion of the refinement cut, the abrasive material 60has been pulverized so that the abrasive material 60 is fractured intofiner particles and, thereby, does not function to remove a substantialamount of material from the surface of the vane. The pulverized abrasivematerial 60 thereby burnishes the vane as a result of the impingingforce of the fluent mass upon the vane. The burnishing of the vane 10imparts compressive stresses to the surface so as to work harden thevane. A preferred abrasive material 60 for the refinement cut isRichwood Compound No. 42, as manufactured by Richwood Industries, Inc.of Garden Grove, Calif.

COLORING COMPOUND

During the rough cut and the refinement cuts, a coloring compound 70 isalso employed. The use of the coloring compound 70 during the rough andrefinement cut cleans the vane 10 so that efficient abrasion may beachieved. In addition, the coloring compound 70 acts to remove foreignmatter from the surface of the vane 10 so that the material is notdriven into the vane 10 when the fluent mass 30 impinges the surface.During the color cycle, the coloring compound 70 is employed without theabrasive material 60 so as to produce a highly reflective finish,thereby making any surface defects or flaws distinctive. Preferably, thecoloring compound 70 comprises a mixture of wood flour, soaps,surfactants, water softening agents, tallow fatty acids and detergents,so as to have a specific gravity less than 0.5 and a water solubility ofapproximately 76%. A preferred coloring compound 70 is Richwood CompoundNo. 43, as manufactured by Richwood Industries, Inc. of Garden Grove,Calif.

LUBRICANT FLUID

A lubricating fluid 80 is employed during the rough cut, refinement cutand color steps to lubricate the surfaces of the fluent mass 30 and thevane 10. In addition, the lubricating fluid 80 dissipates heat generatedby the friction between the fluent mass 30 and the vane 10. Further, thelubricating fluid 80 suspends the abrasive material 60 and coloringcompound 70 so that they may be disposed between the fluent mass 30 andthe surface of the vane 10 during the operations. The lubricating fluid80 also suspends soils and foreign matter so as to prevent the redepositof the material on the vane 10 or the impacting of the soils into thevane.

The amount of lubricating fluid 80 is dictated by the functionalparameters in that if too little lubricating fluid is used, theoperating temperature is increased, which may degrade the vane 10, thefluent mass 30, the abrasive material 60 or the coloring compound 70.Further, too little lubricating fluid 80 does not produce sufficientcleaning as the produced soils are not carried away from the surface ofthe vane 10. If the produced soils are not removed from the surface, theefficiency of the process is substantially reduced. Alternatively, toomuch lubricating fluid 80 retards the action of the fluent mass 30 so asto reduce the amount of energy imparted to the fluent mass, therebypreventing the abrasive from removing material from the surface of thevane 10.

It is preferable that the volume of lubricating fluid 80 range fromapproximately 2 inches below the level of the fluent mass 30 within thebarrel 20 to approximately 2 inches above the level of the fluent mass30 in the barrel 20, so that approximately 80 to 120% of theinterstitial space of the fluent mass 30 is filled by the lubricatingfluid 80. Preferably, a zero fluid level is employed, that is,approximately 100% of the interstitial space of the fluent mass isfilled with the lubricating fluid 80. Although a variety of lubricatingfluids or solutions may be employed, water is the preferred lubricatingfluid.

OPERATION OF THE METHOD

A plurality of vanes 10 are fixtured within the rack so as to preventrelative motion of the vanes 10 relative to the rack. The racked vanes10 are then disposed within the barrel 20, and the rack 40 is fixed withrespect to the barrel 20.

The fluent mass is then added into the barrel 20 to occupy approximately65% of the volume of the barrel. For the rough cut of a vane having asurface texture of approximately 40-50×10⁻⁶ inches rms, the fluent mass30 preferably comprises the preformed ceramic triangles of 5/8"×1/4",such as Richwood Media No. 62, 63 or 64.

For the rough cut, an abrasive material 60, such as Richwood CompoundNo. 40, and the coloring compound 70, such as Richwood Compound No. 43,are added to the barrel. Preferably, approximately 1 cup of the RichwoodCompound No. 40 and 1 cup of the Richwood Compound No. 43 are employedin the rough cut for a barrel 20 having a volume of approximately 1cubic foot filled to approximately 65% with the fluent mass 30. Water asthe lubricating fluid 80 is added to the barrel 20 so that the waterlevel is substantially equal to the level of the fluent mass 30 withinthe barrel. The barrel 20 is then sealed with the lid 22 disposed in theturret, and the turret 22 is then rotated at approximately 150 rpms.Preferably, the abrasive material 60 and coloring compound 70 produce aviscous foam or lather upon rotation of the barrel 20 so as to cushionimpact of the fluent mass 30 and the vane 10. If the surface texture ofthe vane 10 prior to the rough cut is approximately 40×10⁻⁶ inches rms,the turret 22 is rotated for a period of 10 minutes. However, if theprior surface texture of the vane 10 is approximately 125×10⁻⁶ inchesrms, the period of rotation for the rough cut may be increased toapproximately 50 minutes.

After rotation of the barrel 20 in the rough cut step, the barrel isopened and the fluent mass 30 is rinsed with a fresh water. The rinseinvolves twice the volume of the lubricating fluid 80. The rough cutyields a surface texture between 11-27×10⁻⁶ inches rms. After the rinse,a volume of water equal to approximately 100% of the interstitial volumeof the fluent mass 30 in the barrel 20.

Preferably, the scientered ceramic fluent mass 30, such as RichwoodMedia No. 8XM, is used to replace fluent mass 30 used in the rough cut,wherein approximately 65% of the barrel volume is filled with the newfluent mass. For the refinement cut, an abrasive material 60, such asRichwood Compound No. 42, and the coloring compound 70, such as RichwoodCompound No. 43, are added to the barrel 20. Preferably, 1 cup ofRichwood Compound No. 42 and 1 cup of Richwood Compound No. 43 are usedin the refinement cut. The lubricating fluid is preferably at a zerowater level. The barrel 20 is then sealed and rotated at approximately150 rpm for a period of approximately 10 minutes. The refinement cutprocess yields a surface texture between 5-7×10⁻⁶ inches rms. Inaddition, as the abrasive material 60 is pulverized during therefinement cut, the vane 10 is burnished by the impinging fluent mass 30and the pulverized abrasive 60. After the refinement cut rotation, thefluent mass 30, Richwood Media No. 8XM, is then rinsed, and the water isreplaced so that a zero water level remains in the barrel 20.

The coloring compound 70, such as Richwood Compound No. 43, is thenadded to the barrel. Preferably, 1 cup of Richwood Compound No. 43 isused for the color cycle. The barrel 20 is then sealed, and rotated forapproximately 5 minutes at 100-150 rpm. The coloring cycle removes anominal amount of material from the surface of the vane 10, such thatthe final surface texture is approximately 4-7 microinches rms.

After the coloring cycle, the rack 40 is removed from the barrel, andthe vanes 10 are rinsed and released from the rack 40. The highlyreflective surface texture of the vanes 10 permits the ready inspectionof the vanes for surface defects, cracks or other flaws. In addition,the highly reflective finish provides a surface texture which exhibits alower drag force than the surface texture of the prior art. The reduceddrag force also lowers the operating temperature of the vanes 10,thereby prolonging the useful life of the components.

The fluent mass 30 is then discarded, and the process may be restartedfor a new batch of vanes 10.

Although the present invention has been described in terms of particularembodiments, it is not limited to these embodiments. Alternativeembodiments and modifications which would still be encompassed by theinvention may be made by those skilled in the art, particularly in lightof the foregoing teachings. Alternative embodiments, modifications andequivalents may be included within the spirit and scope of the inventionas defined by the claims.

I claim:
 1. An apparatus for providing a surface texture on a pluralityof vanes, comprising:(a) a barrel sized to retain a plurality of vanes;(b) a rack sized to be received with the barrel, such that the rack isconfigured to secure a plurality of vanes within the barrel so as tosubstantially fix the vanes relative to the barrel; (c) a fluent massmovably received within the barrel so that the fluent mass occupies atleast 30% of the volume of the barrel; (d) a lubricating fluid forsubstantially wetting the surface of the fluent mass; (e) an abrasivematerial for abrading the vanes as the fluent mass impinges the vanes soas to produce a surface texture of less than 10×10⁻⁶ rms; and (f)centrifugal barrel finishing means for moving the barrel so that thefluent mass impinges the vanes.
 2. An apparatus as defined in claim 1,wherein the fluent mass comprises particles with sizes in the range of0.0625 inches to 1.25 inches, and wherein the density of the fluent massis in the range of 10 to 300 pounds per cubic foot.
 3. An apparatus asdefined in claim 2, wherein the fluid mass particulates are pyramidalhaving sizes in the range of 4 mesh to 5/8" by 1/4 inch pyramidal.
 4. Anapparatus as defined in claim 3, wherein the fluent mass has a densityin the range of 85 to 150 pounds per cubic foot.
 5. An apparatus asdefined in claim 4, wherein the fluent mass occupies from 30% to 90% ofthe barrel volume.
 6. An apparatus as defined in claim 4, wherein thefluent mass occupies from 50% to 75% of the barrel volume.
 7. Anapparatus as defined in claim 2, wherein the abrasive material is anabrasive in the range of 24 grit to 500 grit.
 8. An apparatus as definedin claim 5, wherein the abrasive material is an abrasive in the range of24 grit to 500 grit.
 9. An apparatus as defined in claim 8, wherein thefluent mass occupies from 50% to 75% of the barrel volume.
 10. Anapparatus as defined in claim 1, wherein the fluent mass comprisesparticulates having sizes in the range of 2 to 20 mesh and wherein thedensity of the fluent mass is in the range of 140 to 150 per cubic foot.11. An apparatus as defined in claim 10, wherein the fluent masscomprises particulates having sizes in the range of 4 to 16 mesh, andwherein the fluent mass occupies 30-90% of the barrel.
 12. An apparatusas defined in claim 11, wherein the fluent mass comprises particulateshaving sizes in the range of 4 to 12 mesh, and wherein the fluent massoccupies 50-75% of the barrel.
 13. An apparatus as defined in claim 10,wherein the abrasive material is an abrasive in the range of 150 grit to1600 grit.
 14. An apparatus as defined in claim 12, wherein the abrasivematerial is an abrasive in the range of 150 grit to 1600 grit and issubstantially insoluble in water.
 15. An apparatus as defined in claim1, wherein the fluent mass has particulate sizes in the range of 2 to 36mesh, with a fluent mass density of about 140 to 150 pounds per cubicfoot.
 16. An apparatus as defined in claim 15, wherein the fluent massoccupies from 50% to 75% of the barrel volume.
 17. An apparatus asdefined in claim 15, wherein the abrasive material has a specificgravity less than 5 and which is partially water soluble.
 18. Anapparatus as defined in claim 16, wherein the abrasive material has aspecific gravity less than 5 and which is partially water soluble.
 19. Amethod for providing a surface texture on a vane, comprising:(a)securing the vane relative to a barrel; (b) introducing a fluent massinto the barrel so that the fluent mass occupies at least 30% of thevolume of the barrel; (c) introducing an abrasive material to the fluentmass so that the abrasive material is substantially disposed on thefluent mass; (d) introducing a lubricating fluid into the barrel tosubstantially wet the surface of the fluent mass; and (e) moving thebarrel in a centrifugal barrel finishing machine so that the fluent masscauses the abrasive material to impinge the blade so as to produce asurface texture of less than 10×10⁻⁶ inches in less than 30 minutes. 20.A method as defined in claim 19, wherein the step of introducing afluent mass comprises introducing particles with sizes in the range of0.0625 inches to 1.25 inches and selected to have a density in the rangeof 10 to 300 pounds per cubic foot.
 21. A method as defined in claim 20,wherein the step of introducing a fluent mass comprises introducingparticles of a pyramidal shape with sizes in the range of 4 mesh to 158" by 1/4inch pyramidal.
 22. A method as defined in claim 21, wherein thestep of introducing a fluent mass comprises introducing fluent masssufficient to occupy from 30% to 90% of the barrel volume.
 23. A methodas defined in claim 21, wherein the step of introducing a fluent masscomprises introducing fluent mass sufficient to occupy from 50% to 75%of the barrel volume.
 24. A method as defined in claim 20, wherein thestep of introducing an abrasive material comprises introducing anabrasive in the range of 24 grit to 500 grit.
 25. A method as defined inclaim 28, wherein the step of introducing an abrasive material comprisesintroducing an abrasive in the range of 24 grit to 500 grit.
 26. Amethod as defined in claim 19, wherein the step of introducing a fluentmass comprises introducing particulates having sizes in the range of 2to 20 mesh and wherein the density of the fluent mass is selected to bein the range of 140 to 150 pounds per cubic foot.
 27. A method asdefined in claim 26, wherein the step of introducing a fluent masscomprises introducing particulates having sizes in the range of 4 to 16mesh to occupy 30-90% of the barrel.
 28. A method as defined in claim27, wherein the step of introducing a fluent mass comprises introducingparticulates having sizes in the range of 4 to 12 mesh to occupy 50-75%of the barrel.
 29. A method as defined in claim 26, wherein the step ofintroducing the abrasive comprises introducing an abrasive in the rangeof 150 grit to 1600 grit.
 30. A method as defined in claim 26, whereinthe step of introducing the abrasive comprises introducing an abrasivein the range of 150 grit to 1600 grit and wherein the abrasive isselected to be substantially insoluble in water.
 31. A method as definedin claim 19, wherein the step of introducing the fluent mass comprisesintroducing particles with sizes in the range of 2 to 36 mesh andselected to have a density of about 140 to 150 pounds per cubic foot.32. A method as defined in claim 31, wherein the step of introducing thefluent mass comprises introducing sufficient fluent mass to occupy from50% to 75% of the barrel volume.
 33. A method as defined in claim 31,wherein the step of introducing abrasive material comprises introducingan abrasive material selected to have a specific gravity less than 5 andwhich is partially soluble in water.
 34. A method as defined in claim32, wherein the step of introducing abrasive material comprisesintroducing an abrasive material selected to have a specific gravityless than 5 and which is partially soluble in water.
 35. A method asdefined in claim 19, wherein the step of introducing lubricating fluidcomprises the step of introducing an amount of lubricating fluidcomprising 80 to 120% of any intersticial space in the fluent mass. 36.A method as defined in claim 24, wherein the step of introducinglubricating fluid comprises the step of introducing an amount oflubricating fluid comprising 80 to 120% of any intersticial space in thefluent mass.
 37. A method as defined in claim 29, wherein the step ofintroducing lubricating fluid comprises the step of introducing anamount of lubricating fluid comprising 80 to 120% of any intersticialspace in the fluent mass.
 38. A method as defined in claim 25, whereinthe step of introducing lubricating fluid comprises the step ofintroducing an amount of lubricating fluid comprising 100% of anyintersticial space of the fluent mass.
 39. A method as defined in claim30, wherein the step of introducing lubricating fluid comprises the stepof introducing an amount of lubricating fluid comprising 100% of anyintersticial space of the fluent mass.